Battery cell and electric device

Abstract

Provided are a battery cell (10) and an electric device. The battery cell (10) comprises a housing (200) and an electrode assembly (100). The electrode assembly (100) comprises a plurality of first electrode sheets (110) and a plurality of second electrode sheets (120) that are stacked. Each first electrode sheet (110) is provided with a first notch (111), and each second electrode sheet (120) is provided with a second notch (121); when observed in a first direction (X), the first notch (111) and the second notch (121) do not overlap. Each first electrode sheet (110) is provided with a first empty foil area (112) at least partially overlapping the second notch (121), and each second electrode sheet (120) is provided with a second empty foil area (122) at least partially overlapping the first notch (111). In the direction of length of the second electrode sheets (120), the distance between the end of each second electrode sheet (120) provided with the second empty foil area (122) and an inner wall of the housing (200) is D1, which satisfies 0.1 mm≤D1≤1.5 mm. The protruding volumes of the first empty foil areas (112) from the first electrode sheets (110) and the second empty foil areas (122) from the second electrode sheets (120) can be reduced, thereby increasing the energy density of the battery cell (10); moreover, when the battery cell (10) is subjected to an external force or drops, the electrode assembly (100) is less likely to shake relative to the housing (200), reducing the risk of thermal runaway in the battery cell (10).

Description

Battery cells and electrical equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application CN202410383508.8, entitled “Battery Cells and Electrical Equipment,” filed on March 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery cell and an electrical device. Background Art

[0003] With the rapid development of electronic information technology, various electronic devices are also developing towards intelligence and multi-functions, and the requirements for various battery performance are becoming higher and higher.

[0004] At present, the tab of the electrode assembly is generally led out from one end of the electrode sheet in the length direction, so that a large space needs to be reserved between the shell for accommodating the electrode assembly and the end of the electrode assembly where the tab is set to accommodate the tab, which affects the energy density of the battery cell and causes the electrode assembly to shake easily relative to the shell when the battery cell is subjected to external force or falls, which may cause a short circuit between the tab and the electrode sheet, thereby increasing the risk of thermal runaway of the battery cell. Summary of the Invention

[0005] The present application provides a battery cell and electrical equipment, which can improve the energy density of the battery cell and reduce the possibility of battery cell short circuit.

[0006] In a first aspect, the present application provides a battery cell, which includes a shell and an electrode assembly, the electrode assembly being accommodated in the shell, the electrode assembly being a laminated structure, the electrode assembly including a plurality of first electrode sheets and a plurality of second electrode sheets stacked along a first direction, the first electrode sheets and the second electrode sheets having opposite polarities, each first electrode sheet having a first notch, each second electrode sheet having a second notch, and the first notch and the second notch not overlapping when viewed along the first direction; each first electrode sheet having a first empty foil area that at least partially overlaps with the second notch, and the first empty foil areas of the plurality of first electrode sheets are stacked along the first direction; each second electrode sheet having a second empty foil area that at least partially overlaps with the first notch, and the second empty foil areas of the plurality of second electrode sheets are stacked along the first direction; the second notch and the second empty foil area are located at one end of the second electrode sheet in a longitudinal direction, and the second notch and the second empty foil area are spaced apart along a width direction of the second electrode sheet; along the longitudinal direction of the second electrode sheet, a distance D1 is between an end of the second electrode sheet provided with the second empty foil area and the second notch and the inner wall of the shell, satisfying 0.1 mm ≤ D1 ≤ 1.5 mm.

[0007] In the above technical solution, each first electrode piece has a first notch, and each second electrode piece has a second notch. When viewed along the first direction, the first notch and the second notch do not overlap; each first electrode piece has a first empty foil area that at least partially overlaps with the second notch, and each second electrode piece has a second empty foil area that at least partially overlaps with the first notch, so that the first empty foil area and the second empty foil area are spaced apart on a vertical plane in the first direction, which can reduce the possibility of short circuit caused by contact between the first empty foil area and the second empty foil area; and at least part of the first empty foil area is accommodated in the second notch, and at least part of the second empty foil area is accommodated in the first notch, which can reduce the first empty foil area and the second empty foil area protruding from the first electrode piece and The volume of the second electrode piece is reduced, and the interval space reserved between the electrode assembly and the shell for accommodating the first empty foil area and the second empty foil area is reduced, which can improve the energy density of the battery cell. When the battery cell is subjected to external force or falls, the electrode assembly is less likely to shake relative to the shell, and the possibility of short circuit between the first empty foil area and the second electrode piece, and the second empty foil area and the first electrode piece is also smaller, thereby reducing the risk of thermal runaway of the battery cell; the first empty foil areas of the plurality of first electrode pieces are stacked along the first direction, and the second empty foil areas of the plurality of second electrode pieces are stacked along the first direction, which facilitates the connection of the plurality of first empty foil areas and the connection of the plurality of second empty foil areas, so that the external device can connect with the plurality of first electrode pieces through the first empty foil area. The first and second electrode sheets are electrically connected, and can be electrically connected to multiple second electrode sheets through the second empty foil area; the second notch and the second empty foil area are located at one end of the length direction of the second electrode sheet, so that the first empty foil area and the second empty foil area can be led out from one end of the length direction of the second electrode sheet, which is convenient for the battery cell to be electrically connected to the external device through the first empty foil area and the second empty foil area; the second notch and the second empty foil area are spaced apart along the width direction of the second electrode sheet, which can reduce the possibility of short circuit between the first empty foil area and the second electrode sheet, and the second empty foil area and the first electrode sheet; when the distance D1 between the end of the second electrode sheet provided with the second empty foil area and the second notch and the inner wall of the shell is greater than or equal to 0.1 mm along the length direction of the second electrode sheet, it can be convenient for the battery cell to be electrically connected to the external device through the first empty foil area and the second empty foil area The assembly of the electrode assembly and the shell, and the accommodation of the electrolyte, are beneficial to improving the cycle life of the battery cell; when the distance D1 between one end of the second electrode sheet with the second empty foil area and the second notch and the inner wall of the shell is less than or equal to 1.5 mm along the length direction of the second electrode sheet, the spacing between the electrode assembly and the shell can be smaller, and the energy density of the battery cell can be higher; therefore, when the distance D1 between one end of the second electrode sheet with the second empty foil area and the second notch and the inner wall of the shell is 0.1 mm-1.5 mm along the length direction of the second electrode sheet, it can facilitate the assembly of the electrode assembly and the shell, and the accommodation of the electrolyte, and is beneficial to improving the cycle life of the battery cell, and can also make the energy density of the battery cell higher.

[0008] In some embodiments of the present application, 0.3 mm ≤ D1 ≤ 1 mm.

[0009] In the above technical solution, when the distance D1 between one end of the second electrode sheet provided with the second empty foil area and the second notch and the inner wall of the outer shell is 0.3mm-1mm along the length direction of the second electrode sheet, it can further facilitate the assembly of the electrode assembly and the outer shell, and accommodate the electrolyte, and can also further make the energy density of the battery cell higher; and if no notch is provided in the battery cell to accommodate the empty foil area, the empty foil area will protrude, occupying the space between the outer shell and the electrode assembly, affecting the energy density of the battery cell. In this solution, a notch is provided in the electrode sheet to accommodate the empty foil area, so that the distance between the end of the second electrode sheet provided with the second empty foil area and the second notch and the inner wall of the outer shell can be limited to within the above range.

[0010] In some embodiments of the present application, the first pole piece has a first angular position and a second angular position, the second pole piece has a third angular position and a fourth angular position, the first notch is located at the first angular position of the first pole piece, and the first empty foil area is located at the second angular position of the first pole piece; the second notch is located at the third angular position of the second pole piece, and the second empty foil area is located at the fourth angular position of the second pole piece.

[0011] In the above technical solution, by making the first notch located at the first corner position of the first electrode, the first empty foil area is located at the second corner position of the first electrode; the second notch is located at the third corner position of the second electrode, and the second empty foil area is located at the fourth corner position of the second electrode, it is possible to facilitate the preparation of the first notch, the first empty foil area, the second notch and the second empty foil area, and facilitate the lead-out of the first empty foil area and the second empty foil area, further reducing the possibility of short circuit between the first empty foil area and the second electrode, and between the second empty foil area and the first electrode.

[0012] In some embodiments of the present application, the first angular position and the second angular position are two adjacent angular positions of the first pole piece; the third angular position and the fourth angular position are two adjacent angular positions of the second pole piece.

[0013] In the above technical solution, the first angular position and the second angular position are two adjacent angular positions of the first electrode piece; the third angular position and the fourth angular position are two adjacent angular positions of the second electrode piece, so that the first empty foil area and the second empty foil area can be led out from the same end of the electrode assembly, making it convenient for the battery cell to be electrically connected to the external device through the first empty foil area and the second empty foil area.

[0014] In some embodiments of the present application, the first pole piece has a first coating area, and along the length direction of the first pole piece, the first empty foil area does not exceed the first coating area; along the width direction of the first pole piece, the first empty foil area does not exceed the first coating area.

[0015] In the above technical solution, along the length direction of the first electrode, the first empty foil area does not exceed the first coated area; along the width direction of the first electrode, the first empty foil area does not exceed the first coated area, so that the first empty foil area and the second empty foil area do not protrude from the first electrode and the second electrode, and there is no need to reserve a spacing space between the electrode assembly and the shell to accommodate the first empty foil area and the second empty foil area, which can further improve the energy density of the battery cell. When the battery cell is subjected to external force or falls, the possibility of the electrode assembly shaking relative to the shell is further reduced, and the possibility of short circuit between the first empty foil area and the second electrode, and the second empty foil area and the first electrode is further reduced, thereby further reducing the risk of thermal runaway of the battery cell.

[0016] In some embodiments of the present application, the first coating area has a first edge in the length direction of the first pole piece and a second edge in the width direction of the first pole piece; the first empty foil area has a third edge in the length direction of the first pole piece and a fourth edge in the width direction of the first pole piece; the third edge is flush with the first edge, and the fourth edge is flush with the second edge.

[0017] In the above technical solution, by making the third edge flush with the first edge and the fourth edge flush with the second edge, the preparation of the first empty foil area and the second empty foil area can be facilitated.

[0018] In some embodiments of the present application, the projection area of ​​the first empty foil area along the first direction is S1, which satisfies 5mm 2 ≤S1≤70mm 2 .

[0019] In the above technical solution, when the projection area S1 of the first empty foil area along the first direction is greater than or equal to 5mm 2 , which can make the area of ​​the first empty foil area larger, facilitate the connection of multiple first empty foil areas, and make the connection reliability of multiple first empty foil areas better; when the projection area S1 of the first empty foil area along the first direction is less than or equal to 70mm 2 , which can make the space occupied by the first empty foil area smaller, which is beneficial to improving the energy density of the battery cell; when the projection area S1 of the first empty foil area along the first direction is 5mm 2 -70mm 2 This can not only improve the connection reliability of multiple first empty foil areas, but also help to improve the energy density of the battery cell.

[0020] In some embodiments of the present application, 10 mm 2 ≤S1≤60mm 2 .

[0021] In the above technical solution, when the projection area S1 of the first empty foil area along the first direction is 10 mm 2 -60 mm 2, which can further improve the connection reliability of multiple first empty foil areas and is conducive to further improving the energy density of the battery cell.

[0022] In some embodiments of the present application, the maximum dimension of the first empty foil area in the length direction of the first electrode piece is L1, satisfying 1mm≤L1≤15mm; the maximum dimension of the first empty foil area in the width direction of the first electrode piece is W1, satisfying 1mm≤W1≤15mm.

[0023] In the above technical solution, when the maximum dimension L1 of the first empty foil area in the length direction of the first pole piece is greater than or equal to 1 mm, and the maximum dimension W1 of the first empty foil area in the width direction of the first pole piece is greater than or equal to 1 mm, the size of the first empty foil area can be made larger, which is convenient for connecting multiple first empty foil areas, and the connection reliability of multiple first empty foil areas is better; when the maximum dimension L1 of the first empty foil area in the length direction of the first pole piece is less than or equal to 15 mm, and the maximum dimension W1 of the first empty foil area in the width direction of the first pole piece is less than or equal to 15 mm, the space occupied by the first empty foil area is smaller, which is beneficial to improving the energy density of the battery cell; when the maximum dimension L1 of the first empty foil area in the length direction of the first pole piece is 1 mm-15 mm, and the maximum dimension W1 of the first empty foil area in the width direction of the first pole piece is 1 mm-15 mm, the connection reliability of multiple first empty foil areas can be better, which is beneficial to improving the energy density of the battery cell.

[0024] In some embodiments of the present application, 3mm≤L1≤10mm, 3mm≤W1≤10mm.

[0025] In the above technical solution, when the maximum dimension L1 of the first empty foil area in the length direction of the first pole piece is 3mm-10mm, and the maximum dimension W1 of the first empty foil area in the width direction of the first pole piece is 3mm-10mm, the connection reliability of the multiple first empty foil areas can be further improved, which is conducive to further improving the energy density of the battery cell.

[0026] In some embodiments of the present application, the area of ​​the first gap is S2, which satisfies 5mm 2 ≤S2≤70mm 2 .

[0027] In the above technical solution, when the area S2 of the first gap is greater than or equal to 5mm 2 , which can make the area of ​​the first gap larger, so as to accommodate the second empty foil area, and reduce the possibility of short circuit between the second empty foil area and the first electrode; when the area S2 of the first gap is less than or equal to 70mm 2 , which can make the space occupied by the first gap smaller, which is beneficial to improving the energy density of the battery cell; when the area S2 of the first gap is 5mm 2-70mm 2 This can not only reduce the possibility of short circuit between the second empty foil area and the first electrode, but also help to improve the energy density of the battery cell.

[0028] In some embodiments of the present application, 10 mm 2 ≤S2≤60mm 2 .

[0029] In the above technical solution, when the area S2 of the first gap is 10mm 2 -60 mm 2 This can not only further reduce the possibility of short circuit between the second empty foil area and the first electrode, but also help to further improve the energy density of the battery cell.

[0030] In some embodiments of the present application, the maximum dimension of the first notch in the length direction of the first pole piece is L2, satisfying 1mm≤L2≤15mm; the maximum dimension of the first notch in the width direction of the first pole piece is W2, satisfying 1mm≤W2≤15mm.

[0031] In the above technical solution, when the maximum dimension L2 of the first notch in the length direction of the first electrode piece is greater than or equal to 1mm, and the maximum dimension W2 of the first notch in the width direction of the first electrode piece is greater than or equal to 1mm, the size of the first notch can be made larger, which is convenient for accommodating the second empty foil area, so that the possibility of the second empty foil area contacting and short-circuiting with the first electrode piece is smaller; when the maximum dimension L2 of the first notch in the length direction of the first electrode piece is less than or equal to 15mm, and the maximum dimension W2 of the first notch in the width direction of the first electrode piece is less than or equal to 15mm, the space occupied by the first notch can be made smaller, which is beneficial to improving the energy density of the battery cell; when the maximum dimension L2 of the first notch in the length direction of the first electrode piece is 1mm-15mm, and the maximum dimension W2 of the first notch in the width direction of the first electrode piece is 1mm-15mm, it can not only reduce the possibility of the second empty foil area contacting and short-circuiting with the first electrode piece, but also help to improve the energy density of the battery cell.

[0032] In some embodiments of the present application, 3mm≤L2≤10mm, 3mm≤W2≤10mm.

[0033] In the above technical solution, when the maximum dimension L2 of the first notch in the length direction of the first pole piece is 3mm-10mm, and the maximum dimension W2 of the first notch in the width direction of the first pole piece is 3mm-10mm, it can not only further reduce the possibility of short circuit between the second empty foil area and the first pole piece, but also help to further improve the energy density of the battery cell.

[0034] In some embodiments of the present application, the electrode assembly further includes a diaphragm, which is disposed between the first electrode plate and the second electrode plate. The diaphragm has a third notch and a fourth notch. Along the first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch.

[0035] In the above technical solution, the diaphragm has a third notch and a fourth notch. Along the first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch, so that the third notch can be used to accommodate the first empty foil area, and the fourth notch can be used to accommodate the second empty foil area, which can facilitate the connection of multiple first empty foil areas and multiple second empty foil areas.

[0036] In some embodiments of the present application, the electrode assembly also includes a diaphragm, the first electrode plate is a positive electrode plate, and the second electrode plate is a negative electrode plate; the battery cell is a soft-pack battery cell, and along the first direction, the edge areas of the two layers of diaphragm located on both sides of the second electrode plate are connected to each other.

[0037] In the above technical solution, since the potential difference between the negative electrode plate and the outer shell in the soft-pack battery cell is greater than the potential difference between the positive electrode plate and the outer shell, if the negative electrode plate contacts the outer shell, the possibility of corrosion of the outer shell is greater. By connecting the edge areas of the two layers of diaphragms on both sides of the second electrode plate along the first direction to each other, the possibility of the second electrode plate contacting the outer shell and corroding the outer shell can be reduced, which is beneficial to extending the service life of the battery cell.

[0038] In some embodiments of the present application, the electrode assembly also includes a diaphragm, the first electrode piece is a positive electrode piece, and the second electrode piece is a negative electrode piece; the battery cell is a hard shell battery cell, and along the first direction, the edge areas of the two layers of diaphragms located on both sides of the first electrode piece are connected to each other.

[0039] In the above technical solution, since in the hard-shell battery cell, the negative electrode plate can be electrically connected to the external device through the outer shell, by connecting the edge areas of the two layers of diaphragms located on both sides of the first electrode plate along the first direction to each other, the possibility of the first electrode plate contacting the outer shell and causing a short circuit between the first electrode plate and the second electrode plate can be reduced, thereby reducing the risk of thermal runaway of the battery cell.

[0040] In some embodiments of the present application, along the first direction, the first empty foil areas of the plurality of first pole pieces are gathered toward the middle and connected; and / or, along the first direction, the second empty foil areas of the plurality of second pole pieces are gathered toward the middle and connected.

[0041] In the above technical solution, along the first direction, the first empty foil areas of the multiple first pole pieces are gathered toward the middle and connected; and / or, along the first direction, the second empty foil areas of the multiple second pole pieces are gathered toward the middle and connected, which can make the connection method of the multiple first empty foil areas and the multiple second empty foil areas simpler and easier to operate, and facilitate the multiple first empty foil areas and the multiple second empty foil areas to lead out the battery cell to be connected to an external device, and can make the size of the first empty foil area and the second empty foil area smaller in their extension direction, so that the space occupied by the first empty foil area and the second empty foil area is smaller, which is beneficial to improving the energy density of the battery cell.

[0042] In some embodiments of the present application, the multiple first empty foil areas include two outer empty foil areas located on the outermost sides, and the angle between the bent edge of the outer empty foil area and the length direction of the first pole piece is α1, satisfying 0<α1≤90°; the angle between the bent edge of the outer empty foil area and the width direction of the first pole piece is α2, satisfying 0<α2≤90°.

[0043] In the above technical solution, by making the angle between the bending edge of the outer empty foil area and the length direction of the first electrode piece α1, satisfying 0<α1≤90°; the angle between the bending edge of the outer empty foil area and the width direction of the first electrode piece α2, satisfying 0<α2≤90°, the bending edge of the outer empty foil area can be inclined relative to the length direction and width direction of the first electrode piece, so that the bending edge is longer and the first empty foil area has higher impact resistance.

[0044] In a second aspect, the present application provides an electrical device, which includes the battery cell as described above, and the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can also be obtained based on these drawings.

[0046] FIG1 is a schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0047] FIG2 is a schematic diagram of an exploded structure of a battery cell provided in some embodiments of the present application;

[0048] FIG3 is a schematic diagram of an exploded structure of an electrode assembly of a battery cell provided in some embodiments of the present application;

[0049] FIG4 is a schematic structural diagram of a first electrode piece of a battery cell provided in some embodiments of the present application;

[0050] FIG5 is a schematic structural diagram of a second pole piece of a battery cell provided in some embodiments of the present application;

[0051] FIG6 is a schematic structural diagram of a battery cell provided in some embodiments of the present application from one perspective;

[0052] FIG7 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along line AA in FIG6 ;

[0053] FIG8 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along line BB in FIG6 ;

[0054] FIG9 is a schematic structural diagram of a diaphragm of a battery cell provided in some embodiments of the present application;

[0055] FIG10 is a schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0056] FIG11 is a partially enlarged schematic diagram of a cross-sectional structure of a portion of the battery cell in FIG10 along CC;

[0057] FIG12 is a schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0058] FIG13 is a partially enlarged schematic diagram of a cross-sectional structure of a portion of the battery cell in FIG12 along line EE.

[0059] Icons: 10-battery cell; 100-electrode assembly; 110-first pole piece; 111-first notch; 112-first empty foil area; 112a-outer empty foil area; 1121-third edge; 1122-fourth edge; 113-first coating area; 1131-first edge; 1132-second edge; 1133-first notch edge; 1133a-first section; 1133b-second section; 1133c-third section; 1134-fifth edge; 114-first adapter; 120-second pole piece; 121-second notch; 122-second empty foil area; 122a-second outer Empty foil area; 1221 - eighth edge; 1222 - ninth edge; 123 - second coating area; 1231 - sixth edge; 1232 - seventh edge; 1233 - second notch edge; 1234 - tenth edge; 124 - second adapter; 130 - diaphragm; 131 - third notch; 1311 - third notch edge; 132 - fourth notch; 1321 - fourth notch edge; 133 - first diaphragm edge; 134 - second diaphragm edge; 135 - third diaphragm edge; 200 - housing; X - first direction; Y - length direction of second electrode piece; Z - width direction of second electrode piece.

[0060] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0061] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0062] The terms "first", "second" and the like in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0063] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0064] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and do not constitute any limitation on this application.

[0065] The battery cell includes a casing and an electrode assembly. The electrode assembly is accommodated in the casing. The electrode assembly includes a pole piece and a tab. The tab generally extends out of the casing from one end of the pole piece in the longitudinal direction to connect to an external device. Therefore, a large space must be reserved between the casing and the end of the electrode assembly where the tab is set to accommodate the tab. This causes the space in the casing used to accommodate the pole piece to be compressed, affecting the energy density of the battery cell. In addition, due to the large spacing between the electrode assembly and the casing, the electrode assembly is prone to shaking relative to the casing when the battery cell is subjected to external force or falls. The tab is fixed relative to the casing, which may cause the tab to move relative to the pole piece, and then short-circuit with the pole piece, resulting in an increased risk of thermal runaway in the battery cell.

[0066] In order to improve the energy density of a battery cell and reduce the possibility of a short circuit in the battery cell, the present application provides a battery cell, which includes an electrode assembly. The electrode assembly is a laminated structure. The electrode assembly includes a plurality of first electrode sheets and a plurality of second electrode sheets stacked along a first direction. The first electrode sheets have opposite polarity to the second electrode sheets. Each first electrode sheet has a first notch, and each second electrode sheet has a second notch. When viewed along the first direction, the first notch and the second notch do not overlap; each first electrode sheet has a first empty foil area that at least partially overlaps with the second notch, and the first empty foil areas of the plurality of first electrode sheets are stacked along the first direction; each second electrode sheet has a second empty foil area that at least partially overlaps with the first notch, and the second empty foil areas of the plurality of second electrode sheets are stacked along the first direction.

[0067] In a battery cell of this structure, each first electrode piece has a first notch, and each second electrode piece has a second notch. When viewed along the first direction, the first notch and the second notch do not overlap; each first electrode piece has a first empty foil area that at least partially overlaps with the second notch, and each second electrode piece has a second empty foil area that at least partially overlaps with the first notch, so that the first empty foil area and the second empty foil area are spaced apart on a vertical plane in the first direction, which can reduce the possibility of short circuit caused by contact between the first empty foil area and the second empty foil area; and at least part of the first empty foil area is accommodated in the second notch, and at least part of the second empty foil area is accommodated in the first notch, which can reduce the volume of the first empty foil area and the second empty foil area protruding from the first electrode piece and the second electrode piece. The interval space reserved between the component and the shell for accommodating the first empty foil area and the second empty foil area is reduced, which can improve the energy density of the battery cell. When the battery cell is subjected to external force or falls, the electrode assembly is less likely to shake relative to the shell, and the possibility of short circuit between the first empty foil area and the second electrode piece, and the second empty foil area and the first electrode piece is also smaller, thereby reducing the risk of thermal runaway of the battery cell; the first empty foil areas of the multiple first electrode pieces are stacked along the first direction, and the second empty foil areas of the multiple second electrode pieces are stacked along the first direction, which facilitates the connection of the multiple first empty foil areas and the multiple second empty foil areas, so that the external device can be electrically connected to the multiple first electrode pieces through the first empty foil area, and can be electrically connected to the multiple second electrode pieces through the second empty foil area.

[0068] The battery cells provided in the embodiments of the present application may be secondary batteries or primary batteries, such as lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, and are not limited in this embodiment. The electrochemical devices may be cylindrical, flat, rectangular, or in other shapes, and are not limited in this embodiment.

[0069] The embodiments of the present application provide an electrical device that uses a battery cell as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, and the like.

[0070] Referring to Figures 1 to 5, Figure 1 is a schematic diagram of the three-dimensional structure of the battery cell provided in some embodiments of the present application; Figure 2 is a schematic diagram of the exploded structure of the battery cell provided in some embodiments of the present application; Figure 3 is a schematic diagram of the exploded structure of the electrode assembly of the battery cell provided in some embodiments of the present application; Figure 4 is a schematic diagram of the structure of the first electrode piece of the battery cell provided in some embodiments of the present application; Figure 5 is a schematic diagram of the structure of the second electrode piece of the battery cell provided in some embodiments of the present application.

[0071] The present embodiment provides a battery cell 10, comprising an electrode assembly 100 and a housing 200. The electrode assembly 100 is housed within the housing 200. The electrode assembly 100 has a laminated structure and includes a plurality of first electrode sheets 110 and a plurality of second electrode sheets 120 stacked along a first direction X. The first electrode sheets 110 and the second electrode sheets 120 have opposite polarities. Each first electrode sheet 110 has a first notch 111, and each second electrode sheet 120 has a second notch 121. When viewed along the first direction X, the first notches 111 and the second notches 121 do not overlap. Each first electrode sheet 110 has a first hollow foil region 112 that at least partially overlaps the second notch 121. The first hollow foil regions 112 of the plurality of first electrode sheets 110 are stacked along the first direction X. Each second electrode sheet 120 has a second hollow foil region 122 that at least partially overlaps the first notch 111. The second hollow foil regions 122 of the plurality of second electrode sheets 120 are stacked along the first direction X.

[0072] By ensuring that each first electrode piece 110 has a first notch 111 and each second electrode piece 120 has a second notch 121, when viewed along the first direction X, the first notch 111 and the second notch 121 do not overlap; each first electrode piece 110 has a first empty foil area 112 that at least partially overlaps with the second notch 121, and each second electrode piece 120 has a second empty foil area 122 that at least partially overlaps with the first notch 111, so that the first empty foil area 112 and the second empty foil area 122 are spaced apart on a vertical plane in the first direction X, the possibility of the first empty foil area 112 and the second empty foil area 122 contacting each other and causing a short circuit can be reduced. In addition, at least a portion of the first empty foil area 112 is accommodated in the second notch 121, and at least a portion of the second empty foil area 122 is accommodated in the first notch 111, which can reduce the volume of the first empty foil area 112 and the second empty foil area 122 protruding from the first electrode sheet 110 and the second electrode sheet 120, and the interval space reserved between the electrode assembly 100 and the shell 200 for accommodating the first empty foil area 112 and the second empty foil area 122 is reduced, which can improve the energy density of the battery cell 10, and when the battery cell 10 is subjected to external force or falls, the electrode assembly 100 is less likely to shake relative to the shell 200, and the possibility of short circuit between the first empty foil area 112 and the second electrode sheet 120, and the second empty foil area 122 and the first electrode sheet 110 is also less, thereby reducing the risk of thermal runaway of the battery cell 10. The first empty foil areas 112 of the multiple first pole pieces 110 are stacked along the first direction X, and the second empty foil areas 122 of the multiple second pole pieces 120 are stacked along the first direction X, so as to facilitate the connection of the multiple first empty foil areas 112 and the connection of the multiple second empty foil areas 122, so that the external device can be electrically connected to the multiple first pole pieces 110 through the first empty foil areas 112, and can be electrically connected to the multiple second pole pieces 120 through the second empty foil areas 122.

[0073] In some embodiments, the second notch 121 and the second empty foil area 122 are located at one end of the second electrode piece in the length direction Y, and the second notch 121 and the second empty foil area 122 are spaced apart along the width direction Z of the second electrode piece.

[0074] By locating the second notch 121 and the second empty foil area 122 at one end of the second electrode sheet in the longitudinal direction Y, the first empty foil area 112 and the second empty foil area 122 can be led out from one end of the second electrode sheet in the longitudinal direction, thereby facilitating electrical connection of the battery cell 10 with an external device via the first empty foil area 112 and the second empty foil area 122. The second notch 121 and the second empty foil area 122 are spaced apart along the width direction Z of the second electrode sheet, thereby reducing the possibility of short circuit between the first empty foil area 112 and the second electrode sheet 120, and between the second empty foil area 122 and the first electrode sheet 110.

[0075] 6 and 7 , FIG6 is a schematic structural diagram of a battery cell provided in some embodiments of the present application from one perspective; FIG7 is a partially enlarged schematic cross-sectional structure diagram of the battery cell along AA in FIG6 .

[0076] In some embodiments, along the length direction Y of the second electrode piece, the distance D1 between the end of the second electrode piece 120 where the second hollow foil area 122 and the second notch 121 are provided and the inner wall of the housing 200 satisfies 0.1 mm ≤ D1 ≤ 1.5 mm. For example, D1 can be 0.1 mm, 0.7 mm, or 1.5 mm.

[0077] When the distance D1 between the end of the second electrode 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the shell 200 is greater than or equal to 0.1 mm along the length direction Y of the second electrode, it is convenient to assemble the electrode assembly 100 and the shell 200, and to accommodate more electrolyte, which can reduce the possibility of the battery cell 10 appearing to be in a cycle, thereby facilitating the cycle life of the battery cell. When the distance D1 between the end of the second electrode 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the shell 200 is greater than or equal to 0.1 mm along the length direction Y of the second electrode, it is convenient to assemble the electrode assembly 100 and the shell 200, and to accommodate more electrolyte, and to reduce the possibility of the battery cell 10 appearing to be in a cycle, thereby facilitating the cycle life of the battery cell. The distance D1 of the inner wall is less than or equal to 1.5 mm, which can make the spacing between the electrode assembly 100 and the outer shell 200 smaller, and the energy density of the battery cell 10 higher; therefore, when along the length direction Y of the second electrode sheet, the distance D1 between one end of the second electrode sheet 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the outer shell 200 is 0.1 mm-1.5 mm, which can facilitate the assembly of the electrode assembly 100 and the outer shell 200, and accommodate the electrolyte, and is beneficial to improving the cycle life of the battery cell 10, and can also make the energy density of the battery cell 10 higher.

[0078] In some embodiments of the present application, 0.3 mm ≤ D1 ≤ 1 mm. For example, D1 may be 0.3 mm, 0.6 mm, or 1 mm.

[0079] When the distance D1 between one end of the second electrode sheet 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the housing 200 is 0.3 mm to 1 mm along the length direction Y of the second electrode sheet, it can further facilitate the assembly of the electrode assembly 100 and the housing 200, as well as the accommodation of the electrolyte, and can also further increase the energy density of the battery cell 10. In addition, if a notch is not provided in the battery cell 10 to accommodate the empty foil area, the empty foil area will need to be electrically connected to an external device, and thus the empty foil area will protrude from one end of the electrode sheet in the length direction, occupying the space between the housing 200 and the electrode assembly 100, thereby affecting the energy density of the battery cell 10. In this solution, a notch is provided in the electrode sheet to accommodate the empty foil area, so that the distance between the end of the second electrode sheet 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the housing 200 can be limited to within the above range.

[0080] In some embodiments, the first notch 111 and the first empty foil area 112 are located at one end of the first electrode in the length direction, and the first notch 111 and the first empty foil area 112 are spaced apart along the width direction of the first electrode.

[0081] By locating the first notch 111 and the first empty foil area 112 at one end of the lengthwise direction of the first electrode sheet, the first empty foil area 112 and the second empty foil area 122 can be led out from one end of the lengthwise direction of the first electrode sheet, facilitating electrical connection of the battery cell 10 to an external device via the first empty foil area 112 and the second empty foil area 122. The first notch 111 and the first empty foil area 112 are spaced apart along the widthwise direction of the first electrode sheet, thereby reducing the possibility of short circuits between the first empty foil area 112 and the second electrode sheet 120, and between the second empty foil area 122 and the first electrode sheet 110.

[0082] In some embodiments of the present application, the first electrode 110 has a first angular position and a second angular position, the second electrode 120 has a third angular position and a fourth angular position, the first notch 111 is located at the first angular position of the first electrode 110, and the first empty foil area 112 is located at the second angular position of the first electrode 110. The second notch 121 is located at the third angular position of the second electrode 120, and the second empty foil area 122 is located at the fourth angular position of the second electrode 120.

[0083] By locating the first notch 111 at the first corner of the first electrode 110 and the first empty foil area 112 at the second corner of the first electrode 110; the second notch 121 at the third corner of the second electrode 120 and the second empty foil area 122 at the fourth corner of the second electrode 120, the preparation of the first notch 111, the first empty foil area 112, the second notch 121 and the second empty foil area 122 can be facilitated, and the first empty foil area 112 and the second empty foil area 122 can be easily led out, further reducing the possibility of short circuit between the first empty foil area 112 and the second electrode 120, and between the second empty foil area 122 and the first electrode 110.

[0084] The angular position in this application refers to the position at the top corner of the pole piece. For example, the first empty foil area 112 is located at the second angular position of the first pole piece 110, that is, the two edges of the first empty foil area 112 and the angle between the two edges coincide with two edges of the first pole piece 110 and the angle between the two edges.

[0085] In other embodiments, the first notch 111 may also be provided at other portions of the first pole piece 110, such as between two adjacent corners of the first pole piece 110. The second notch 121 may also be provided at other portions of the second pole piece 120, such as between two adjacent corners of the second pole piece 120.

[0086] In some embodiments of the present application, the first angular position and the second angular position are two adjacent angular positions of the first pole piece 110 , and the third angular position and the fourth angular position are two adjacent angular positions of the second pole piece 120 .

[0087] By making the first angular position and the second angular position two adjacent angular positions of the first electrode piece 110; and the third angular position and the fourth angular position two adjacent angular positions of the second electrode piece 120, the first empty foil area 112 and the second empty foil area 122 can be led out from the same end of the electrode assembly 100, so that the battery cell 10 is electrically connected to an external device through the first empty foil area 112 and the second empty foil area 122.

[0088] In other embodiments, the first and second angles may be two opposite angles of the first electrode 110. The third and fourth angles may be two opposite angles of the second electrode 120. This can be applied to a structure where the first and second empty foil regions 112, 122 need to be led out from opposite ends of the battery cell 10.

[0089] In some embodiments, the shell 200 can be made of a material with higher strength, such as metal materials such as steel, aluminum alloy, etc., so that the shell 200 has higher acceptance performance, and thus the shell 200 is not easily deformed or damaged due to force or environmental changes, thereby making the battery cell 10 more reliable.

[0090] In other embodiments, the housing 200 may also be made of non-metallic materials with relatively high strength, such as carbon fiber, hard plastic, etc.

[0091] Refer to FIG8 , which is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along line BB in FIG6 .

[0092] In some embodiments, along the width direction Z of the second electrode piece, the distance D2 between the end of the second electrode piece 120 where the second notch 121 is provided and the inner wall of the housing 200 satisfies 0.1 mm ≤ D2 ≤ 1.5 mm. For example, D2 can be 0.1 mm, 0.7 mm, or 1.5 mm.

[0093] When along the width direction Z of the second electrode sheet, the distance D2 between the end of the second electrode sheet 120 provided with the second notch 121 and the inner wall of the outer shell 200 is greater than or equal to 0.1 mm, which can facilitate the assembly of the electrode assembly 100 and the outer shell 200 and the accommodation of the electrolyte; when along the width direction Z of the second electrode sheet, the distance D2 between the end of the second electrode sheet 120 provided with the second notch 121 and the inner wall of the outer shell 200 is less than or equal to 1.5 mm, which can make the interval between the electrode assembly 100 and the outer shell 200 smaller and the energy density of the battery cell 10 higher; therefore, when along the width direction Z of the second electrode sheet, the distance D2 between the end of the second electrode sheet 120 provided with the second notch 121 and the inner wall of the outer shell 200 is 0.1 mm-1.5 mm, which can facilitate the assembly of the electrode assembly 100 and the outer shell 200 and the accommodation of the electrolyte, and can also make the energy density of the battery cell 10 higher.

[0094] In some embodiments, 0.3 mm ≤ D2 ≤ 1 mm. For example, D2 may be 0.3 mm, 0.6 mm, or 1 mm.

[0095] When along the width direction Z of the second electrode sheet, the distance D2 between the end of the second electrode sheet 120 provided with the second notch 121 and the inner wall of the shell 200 is 0.3mm-1mm, which can further facilitate the assembly of the electrode assembly 100 and the shell 200, and accommodate the electrolyte, and can also further make the energy density of the battery cell 10 higher.

[0096] In some embodiments, along the length direction Y of the second electrode piece, the distance between the end of the second electrode piece 120 opposite to the second hollow foil area 122 and the second notch 121 and the inner wall of the housing 200 is 0.1 mm-1.5 mm.

[0097] In some embodiments, along the width direction Z of the second electrode piece, the distance between the end of the second electrode piece 120 where the second empty foil area 122 is provided and the inner wall of the housing 200 is 0.1 mm-1.5 mm.

[0098] 4 , in some embodiments of the present application, the first electrode 110 has a first coated area 113. Along the length direction of the first electrode, the first hollow foil area 112 does not exceed the first coated area 113. Along the width direction of the first electrode, the first hollow foil area 112 does not exceed the first coated area 113.

[0099] In the above technical solution, along the length direction of the first electrode sheet, the first empty foil area 112 does not exceed the first coated area 113; along the width direction of the first electrode sheet, the first empty foil area 112 does not exceed the first coated area 113, so that the first empty foil area 112 does not protrude from the first electrode sheet 110, and there is no need to reserve an accommodation space for the first empty foil area 112 between the electrode assembly 100 and the shell 200, which can further improve the energy density of the battery cell 10, and when the battery cell 10 is subjected to external force or falls, the possibility of the electrode assembly 100 shaking relative to the shell 200 is further reduced, and the possibility of the first empty foil area 112 contacting and short-circuiting with the second electrode sheet 120 is also further reduced, thereby further reducing the risk of thermal runaway of the battery cell 10.

[0100] In some embodiments, the electrode includes a current collector and an active material layer, the coated area is the area where the current collector is coated with the active material layer, and the empty foil area is the area where the current collector is not coated with the active material layer.

[0101] In some embodiments of the present application, the first coating area 113 has a first edge 1131 in the length direction of the first electrode piece and a second edge 1132 in the width direction of the first electrode piece; the first empty foil area 112 has a third edge 1121 in the length direction of the first electrode piece and a fourth edge 1122 in the width direction of the first electrode piece; the third edge 1121 is flush with the first edge 1131, and the fourth edge 1122 is flush with the second edge 1132.

[0102] By making the third edge 1121 flush with the first edge 1131 and the fourth edge 1122 flush with the second edge 1132 , the preparation of the first empty foil area 112 can be facilitated.

[0103] In some embodiments of the present application, the projection area of ​​the first empty foil area 112 along the first direction X is S1, which satisfies the 5mm 2 ≤S1≤70mm 2 For example, S1 can be 5mm 2 , 50mm 2 or 70mm 2 wait.

[0104] When the projection area S1 of the first empty foil area 112 along the first direction X is greater than or equal to 5 mm 2 , which can make the area of ​​the first empty foil area 112 larger, facilitate the connection of multiple first empty foil areas 112, and make the connection reliability of multiple first empty foil areas 112 better; when the projection area S1 of the first empty foil area 112 along the first direction X is less than or equal to 70mm 2 , which can make the space occupied by the first empty foil area 112 smaller, which is beneficial to improving the energy density of the battery cell 10; when the projection area S1 of the first empty foil area 112 along the first direction X is 5mm2 -70mm 2 This can not only improve the connection reliability of the multiple first empty foil areas 112 , but also help to improve the energy density of the battery cell 10 .

[0105] In some embodiments of the present application, 10 mm 2 ≤S1≤60mm 2 For example, S1 can be 10mm 2 , 35mm 2 or 60mm 2 wait.

[0106] When the projection area S1 of the first empty foil area 112 along the first direction X is 10 mm 2 -60 mm 2 , that is, it can further improve the connection reliability of the multiple first empty foil areas 112 and is beneficial to further improve the energy density of the battery cell 10.

[0107] In some embodiments of the present application, the maximum dimension of the first hollow foil region 112 in the length direction of the first electrode sheet is L1, satisfying 1 mm ≤ L1 ≤ 15 mm. For example, L1 can be 1 mm, 8 mm, or 15 mm. The maximum dimension of the first hollow foil region 112 in the width direction of the first electrode sheet is W1, satisfying 1 mm ≤ W1 ≤ 15 mm. For example, W1 can be 1 mm, 7 mm, or 15 mm.

[0108] When the maximum dimension L1 of the first empty foil area 112 in the length direction of the first electrode sheet is greater than or equal to 1 mm, and the maximum dimension W1 of the first empty foil area 112 in the width direction of the first electrode sheet is greater than or equal to 1 mm, the size of the first empty foil area 112 can be made larger, which facilitates the connection of multiple first empty foil areas 112 and improves the connection reliability of the multiple first empty foil areas 112; when the maximum dimension L1 of the first empty foil area 112 in the length direction of the first electrode sheet is less than or equal to 15 mm, and the maximum dimension W1 of the first empty foil area 112 in the width direction of the first electrode sheet is less than or equal to 15 mm, the space occupied by the first empty foil area 112 can be made smaller, which is beneficial to improving the energy density of the battery cell 10; when the maximum dimension L1 of the first empty foil area 112 in the length direction of the first electrode sheet is 1 mm-15 mm, and the maximum dimension W1 of the first empty foil area 112 in the width direction of the first electrode sheet is 1 mm-15 mm, the connection reliability of the multiple first empty foil areas 112 can be improved, which is beneficial to improving the energy density of the battery cell 10.

[0109] In some embodiments of the present application, 3 mm ≤ L1 ≤ 10 mm, and 3 mm ≤ W1 ≤ 10 mm. For example, L1 may be 3 mm, 6 mm, or 10 mm. For example, W1 may be 3 mm, 7 mm, or 10 mm.

[0110] When the maximum dimension L1 of the first empty foil area 112 in the length direction of the first pole piece is 3mm-10mm, and the maximum dimension W1 of the first empty foil area 112 in the width direction of the first pole piece is 3mm-10mm, the connection reliability of the plurality of first empty foil areas 112 can be further improved, which is beneficial to further improve the energy density of the battery cell 10.

[0111] In some embodiments of the present application, the area of ​​the first notch 111 is S2, which satisfies 5mm 2 ≤S2≤70mm 2 For example, S2 can be 5mm 2 , 70mm 2 or 70mm 2 wait.

[0112] The area of ​​the first notch 111 is the projected area of ​​the portion enclosed by the first notch edge 1133, the extension line of the first edge 1131 of the first electrode piece 110, and the extension line of the fifth edge 1134 in the first direction X. The fifth edge 1134 is disposed opposite the second edge 1132 in the width direction of the first electrode piece.

[0113] When the area S2 of the first notch 111 is greater than or equal to 5 mm 2 , which can make the area of ​​the first notch 111 larger, so as to accommodate the second empty foil area 122, and reduce the possibility of the second empty foil area 122 contacting and short-circuiting with the first electrode 110; when the area S2 of the first notch 111 is less than or equal to 70mm 2 , which can make the space occupied by the first notch 111 smaller, which is beneficial to improving the energy density of the battery cell 10; when the area S2 of the first notch 111 is 5mm 2 -70mm 2 This can not only reduce the possibility of short circuit between the second empty foil area 122 and the first electrode 110 , but also help to improve the energy density of the battery cell 10 .

[0114] In some embodiments of the present application, 10 mm 2 ≤S2≤60mm 2 For example, S2 can be 10mm 2 , 45mm 2 or 60mm 2 wait.

[0115] When the area S2 of the first notch 111 is 10 mm 2 -60 mm 2 This can not only further reduce the possibility of short circuit between the second empty foil area 122 and the first electrode 110 , but also help to further improve the energy density of the battery cell 10 .

[0116] In some embodiments of the present application, the maximum dimension of the first notch 111 in the length direction of the first pole piece is L2, satisfying 1mm≤L2≤15mm. For example, L2 can be 1mm, 7.5mm, or 15mm. The maximum dimension of the first notch 111 in the width direction of the first pole piece is W2, satisfying 1mm≤W2≤15mm. For example, W2 can be 1mm, 8.5mm, or 15mm.

[0117] The maximum dimension of the first notch 111 in the length direction of the first pole piece, that is, the maximum distance between the first notch edge 1133 and the extension line of the first edge 1131 of the first pole piece 110 in the length direction of the first pole piece.

[0118] The maximum dimension of the first notch 111 in the width direction of the first pole piece is the maximum distance between the first notch edge 1133 and the extension line of the fifth edge 1134 of the first pole piece 110 in the width direction of the first pole piece.

[0119] When the maximum dimension L2 of the first notch 111 in the length direction of the first electrode sheet is greater than or equal to 1 mm, and the maximum dimension W2 of the first notch 111 in the width direction of the first electrode sheet is greater than or equal to 1 mm, the size of the first notch 111 can be made larger, which is convenient for accommodating the second empty foil area 122, so that the possibility of the second empty foil area 122 contacting and short-circuiting with the first electrode sheet 110 is reduced; when the maximum dimension L2 of the first notch 111 in the length direction of the first electrode sheet is less than or equal to 15 mm, and the maximum dimension W2 of the first notch 111 in the width direction of the first electrode sheet is less than or equal to 15 mm, the space occupied by the first notch 111 can be reduced, which is beneficial to improving the energy density of the battery cell 10; when the maximum dimension L2 of the first notch 111 in the length direction of the first electrode sheet is 1 mm-15 mm, and the maximum dimension W2 of the first notch 111 in the width direction of the first electrode sheet is 1 mm-15 mm, it can reduce the possibility of the second empty foil area 122 contacting and short-circuiting with the first electrode sheet 110, and is beneficial to improving the energy density of the battery cell 10.

[0120] In some embodiments of the present application, 3 mm ≤ L2 ≤ 10 mm, and 3 mm ≤ W2 ≤ 10 mm. For example, L2 can be 3 mm, 6.5 mm, or 10 mm. For example, W2 can be 3 mm, 6 mm, or 10 mm.

[0121] When the maximum dimension L2 of the first notch 111 in the length direction of the first electrode sheet is 3mm-10mm, and the maximum dimension W2 of the first notch 111 in the width direction of the first electrode sheet is 3mm-10mm, it can further reduce the possibility of short circuit between the second empty foil area 122 and the first electrode sheet 110, and is conducive to further improving the energy density of the battery cell 10.

[0122] In some embodiments, the first notch edge 1133 is configured in a broken line shape. For example, as shown in FIG4 , the first notch edge 1133 includes a first segment 1133a, a second segment 1133b, and a third segment 1133c. The first segment 1133a is parallel to the length direction of the first electrode sheet, the second segment 1133b is parallel to the width direction of the first electrode sheet, and the third segment 1133c is connected between the first segment 1133a and the second segment 1133b and is inclined relative to the length direction and the width direction of the first electrode sheet, respectively. This can increase the area of ​​the first notch 111 and facilitate calculation of the area of ​​the active material layer of the first electrode sheet 110.

[0123] In other embodiments, the first notch edge 1133 may also be in a straight line shape, an arc shape, etc.

[0124] In some embodiments, the second notch edge 1233 may be in a broken line shape, a straight line shape, an arc shape, etc. The shape of the second notch edge 1233 is similar to the shape of the first notch edge 1133 and will not be repeated here.

[0125] In some embodiments, the edge of the first empty foil area 112 is in the shape of a broken line, a straight line, an arc, etc.

[0126] In some embodiments, the edge of the second empty foil area 122 may be in a fold line shape, a straight line shape, an arc shape, or the like.

[0127] Referring to FIG. 5 , in some embodiments, the second electrode sheet 120 has a second coated area 123. Along the length direction Y of the second electrode sheet, the second hollow foil area 122 does not extend beyond the second coated area 123. Along the width direction Z of the second electrode sheet, the second hollow foil area 122 does not extend beyond the second coated area 123. This prevents the second hollow foil area 122 from protruding beyond the second electrode sheet 120, eliminating the need to reserve space between the electrode assembly 100 and the housing 200 to accommodate the second hollow foil area 122. This further improves the energy density of the battery cell 10. Furthermore, when the battery cell 10 is subjected to external force or dropped, the likelihood of the electrode assembly 100 shaking relative to the housing 200 is further reduced. The likelihood of the second hollow foil area 122 contacting and short-circuiting with the first electrode sheet 110 is also further reduced, further reducing the risk of thermal runaway in the battery cell 10.

[0128] In some embodiments, the second coated area 123 has a sixth edge 1231 in the length direction Y of the second electrode sheet and a seventh edge 1232 in the width direction Z of the second electrode sheet; the second hollow foil area 122 has an eighth edge 1221 in the length direction Y of the second electrode sheet and a ninth edge 1222 in the width direction Z of the second electrode sheet; the eighth edge 1221 is flush with the sixth edge 1231, and the ninth edge 1222 is flush with the seventh edge 1232. This facilitates the preparation of the second hollow foil area 122.

[0129] In some embodiments, the projection area of ​​the second empty foil area 122 along the first direction X is S3, which satisfies the 5mm 2 ≤S3≤70mm 2 For example, S3 can be 5mm 2 , 50mm 2 or 70mm 2 This can not only improve the connection reliability of the plurality of second empty foil areas 122 , but also help to increase the energy density of the battery cell 10 .

[0130] In some embodiments, the maximum dimension of the second hollow foil area 122 in the length direction Y of the second electrode sheet is L3, satisfying 1mm≤L3≤15mm. For example, L3 can be 1mm, 8mm, or 15mm. The maximum dimension of the second hollow foil area 122 in the width direction Z of the second electrode sheet is W3, satisfying 1mm≤W3≤15mm. For example, W3 can be 1mm, 7mm, or 15mm. This improves the connection reliability of the multiple second hollow foil areas 122 and helps increase the energy density of the battery cell 10.

[0131] In some embodiments, the area of ​​the second notch 121 is S4, which satisfies the 5mm 2 ≤S4≤70mm 2 For example, S4 can be 5mm 2 , 40mm 2 or 70mm 2 wait.

[0132] The area of ​​the second notch 121 is the projected area of ​​the portion enclosed by the second notch edge 1233, the extension lines of the sixth edge 1231 of the second electrode sheet 120, and the extension lines of the tenth edge 1234 in the first direction X. The tenth edge 1234 is disposed opposite the seventh edge 1232 in the width direction Z of the second electrode sheet. This reduces the likelihood of a short circuit between the first hollow foil area 112 and the second electrode sheet 120 and helps improve the energy density of the battery cell 10.

[0133] In some embodiments, the maximum dimension of the second notch 121 in the length direction Y of the second electrode sheet is L4, satisfying 1mm≤L4≤15mm. For example, L4 can be 1mm, 7.5mm, or 15mm. The maximum dimension of the second notch 121 in the width direction Z of the second electrode sheet is W4, satisfying 1mm≤W4≤15mm. For example, W4 can be 1mm, 8.5mm, or 15mm. This can reduce the possibility of short circuit between the first empty foil area 112 and the second electrode sheet 120, and is conducive to improving the energy density of the battery cell 10.

[0134] The maximum dimension of the second notch 121 in the length direction Y of the second pole piece is the maximum distance between the second notch edge 1233 and the extension line of the sixth edge 1231 of the second pole piece 120 in the length direction Y of the second pole piece.

[0135] The maximum dimension of the second notch 121 in the width direction Z of the second pole piece is, that is, the maximum distance between the second notch edge 1233 and the extension line of the tenth edge 1234 of the second pole piece 120 in the width direction Z of the second pole piece.

[0136] 3 and 9 , FIG9 is a schematic structural diagram of a diaphragm of a battery cell provided in some embodiments of the present application.

[0137] In some embodiments of the present application, the electrode assembly 100 further includes a diaphragm 130, which is disposed between the first electrode piece 110 and the second electrode piece 120. The diaphragm 130 has a third notch 131 and a fourth notch 132. Along the first direction X, the first empty foil area 112 at least partially overlaps with the third notch 131, and the second empty foil area 122 at least partially overlaps with the fourth notch 132.

[0138] By providing the diaphragm 130 with a third notch 131 and a fourth notch 132, along the first direction X, the first empty foil area 112 at least partially overlaps with the third notch 131, and the second empty foil area 122 at least partially overlaps with the fourth notch 132, so that the third notch 131 can be used to accommodate the first empty foil area 112, and the fourth notch 132 can be used to accommodate the second empty foil area 122, which can facilitate the connection of multiple first empty foil areas 112 and multiple second empty foil areas 122.

[0139] In some embodiments, the area of ​​the third notch 131 is S5, which satisfies the requirement of 5 mm. 2 ≤S5≤70mm 2 For example, S5 can be 5mm 2 , 30mm 2 or 70mm 2 wait.

[0140] The area of ​​the third notch 131 is the projected area of ​​the portion enclosed by the third notch edge 1311 and the extension lines of the first and second diaphragm edges 133, 134 of the diaphragm 130 in the first direction X. The first diaphragm edge 133 is the edge of the diaphragm in the longitudinal direction where the third notch 131 and the fourth notch 132 are provided, and the second diaphragm edge 134 is the edge of the diaphragm in the width direction where the third notch 131 is provided.

[0141] When the area S5 of the third notch 131 is greater than or equal to 5 mm 2 , which can make the area of ​​the third notch 131 larger, so as to accommodate the first empty foil area 112; when the area S5 of the third notch 131 is less than or equal to 70mm 2 , which can make the space occupied by the third notch 131 smaller, which is beneficial to improving the energy density of the battery cell 10 and has a better isolation effect between the first empty foil area 112 and the second electrode 120; when the area S5 of the third notch 131 is 5mm 2 -70mm 2 , which can not only easily accommodate the first empty foil area 112 , but also help to improve the energy density of the battery cell 10 , and has a better isolation effect between the first empty foil area 112 and the second electrode 120 .

[0142] In some embodiments, the length direction of the first pole piece, the length direction Y of the second pole piece, and the length direction of the diaphragm are parallel to each other. The width direction of the first pole piece, the width direction Y of the second pole piece, and the width direction of the diaphragm are parallel to each other.

[0143] In some embodiments, 10 mm 2 ≤S5≤60mm 2 For example, S5 can be 10mm 2 , 45mm 2 or 60mm 2 It can not only further facilitate the accommodation of the first empty foil area 112 , but also be beneficial to further improve the energy density of the battery cell 10 , and provide a better isolation effect between the first empty foil area 112 and the second electrode 120 .

[0144] In some embodiments, the maximum dimension of the third notch 131 in the longitudinal direction of the diaphragm is L5, satisfying 1mm≤L5≤15mm. For example, L5 can be 1mm, 7.5mm, or 15mm. The maximum dimension of the third notch 131 in the width direction of the diaphragm is W5, satisfying 1mm≤W5≤15mm. For example, W5 can be 1mm, 8.5mm, or 15mm. This facilitates accommodating the first empty foil area 112 while also improving the energy density of the battery cell 10 and providing better isolation between the first empty foil area 112 and the second electrode 120.

[0145] In some embodiments, 3mm≤L5≤10mm, and 3mm≤W5≤10mm. For example, L5 can be 3mm, 6.5mm, or 10mm. For example, W5 can be 3mm, 6mm, or 10mm. This not only facilitates accommodating the first empty foil area 112, but also helps further improve the energy density of the battery cell 10 and provides better isolation between the first empty foil area 112 and the second electrode sheet 120.

[0146] In some embodiments, the area of ​​the fourth notch 132 is S6, which satisfies the 5mm 2 ≤S6≤70mm 2 For example, S6 can be 5mm 2 , 35mm 2 or 70mm 2 It can not only easily accommodate the second empty foil area 122 , but also help to improve the energy density of the battery cell 10 , and has a good isolation effect between the second empty foil area 122 and the first electrode 110 .

[0147] The area of ​​the fourth notch 132 is the projected area of ​​the portion enclosed by the fourth notch edge 1321 and the extension lines of the first diaphragm edge 133 and the third diaphragm edge 135 of the diaphragm 130 in the first direction X. The third diaphragm edge 135 is the edge opposite to the second diaphragm edge 134 in the width direction of the diaphragm.

[0148] In some embodiments, 10 mm 2 ≤S6≤60mm 2 For example, S6 can be 10mm 2 , 45mm 2 or 60mm 2 It can not only further facilitate the accommodation of the second empty foil area 122 , but also be beneficial to further improve the energy density of the battery cell 10 , and provide a better isolation effect between the second empty foil area 122 and the first electrode sheet 110 .

[0149] In some embodiments, the maximum dimension of the fourth notch 132 in the longitudinal direction of the diaphragm is L6, satisfying 1mm≤L6≤15mm. For example, L6 can be 1mm, 7.5mm, or 15mm. The maximum dimension of the fourth notch 132 in the width direction of the diaphragm is W6, satisfying 1mm≤W6≤15mm. For example, W6 can be 1mm, 8.5mm, or 15mm. This facilitates accommodating the second empty foil area 122, helps improve the energy density of the battery cell 10, and provides better isolation between the second empty foil area 122 and the first electrode 110.

[0150] In some embodiments, 3mm≤L6≤10mm, and 3mm≤W6≤10mm. For example, L6 can be 3mm, 6.5mm, or 10mm. For example, W6 can be 3mm, 6mm, or 10mm. This not only facilitates accommodating the second empty foil area 122, but also helps further improve the energy density of the battery cell 10 and provides better isolation between the second empty foil area 122 and the first electrode sheet 110.

[0151] 1 , 10 and 11 , FIG10 is a schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application, and FIG11 is a partially enlarged schematic diagram of a cross-sectional structure of a partial structure of the battery cell in FIG10 along CC.

[0152] In some embodiments of the present application, the electrode assembly 100 further includes a separator 130, the first electrode sheet 110 is a positive electrode sheet, and the second electrode sheet 120 is a negative electrode sheet. The battery cell 10 is a pouch cell 10, and the edges of the two separators 130 located on both sides of the second electrode sheet 120 are connected to each other along the first direction X.

[0153] Since in the soft-pack battery cell 10, the potential difference between the negative electrode sheet and the outer shell 200 is greater than the potential difference between the positive electrode sheet and the outer shell 200, if the negative electrode sheet contacts the outer shell 200, the possibility of corrosion of the outer shell 200 is relatively high. By interconnecting the edge areas of the two layers of diaphragm 130 located on both sides of the second electrode sheet 120 along the first direction X, the possibility of corrosion of the outer shell 200 due to contact between the second electrode sheet 120 and the outer shell 200 can be reduced, which is beneficial to extending the service life of the battery cell 10.

[0154] In other embodiments of the present application, the electrode assembly 100 further includes a separator 130, the first electrode sheet 110 is a positive electrode sheet, and the second electrode sheet 120 is a negative electrode sheet. The battery cell 10 is a hard-shell battery cell 10, and the edges of the two separators 130 located on both sides of the first electrode sheet 110 are connected to each other along the first direction X.

[0155] Since in the hard-shell battery cell 10, the negative electrode plate can be electrically connected to an external device through the outer shell 200, by connecting the edge areas of the two layers of diaphragm 130 located on both sides of the first electrode plate 110 along the first direction X to each other, the possibility of the first electrode plate 110 and the second electrode plate 120 being short-circuited due to contact between the first electrode plate 110 and the outer shell 200 can be reduced, thereby reducing the risk of thermal runaway of the battery cell 10.

[0156] The battery cell 10 includes an electrode assembly 100, a shell 200 and an electrolyte, and the shell 200 is used to accommodate the electrode assembly 100 and the electrolyte. The electrode assembly 100 is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell 10 mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The part of the positive electrode collector that is not coated with the positive electrode active material layer serves as a positive electrode tab (i.e., the first empty foil area 112) to realize the input or output of electrical energy of the positive electrode sheet through the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary material or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The portion of the negative electrode current collector not coated with the negative electrode active material layer serves as the negative electrode tab (i.e., the second empty foil area 122), so that electrical energy can be input or output from the negative electrode sheet through the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be made of carbon or silicon. The separator can be made of polypropylene (PP) or polyethylene (PE). The electrolyte can include an organic solvent, an electrolyte lithium salt, etc.

[0157] In some embodiments, the width of the portion of the diaphragm 130 extending beyond the second pole piece 120 along the direction perpendicular to the first direction X is W5, satisfying 0.1 mm ≤ D3 ≤ 2 mm. For example, D3 may be 0.1 mm, 1 mm, or 2 mm. When the width D3 of the portion of the diaphragm 130 extending beyond the second electrode piece 120 along the perpendicular direction of the first direction X is greater than or equal to 0.1 mm, it is possible to facilitate the mutual connection of the edge areas of the two layers of diaphragms 130 on both sides of the first electrode piece 110 or the second electrode piece 120, thereby reducing the possibility of short circuit between the first electrode piece 110 and the second electrode piece 120; when the width D3 of the portion of the diaphragm 130 extending beyond the second electrode piece 120 along the perpendicular direction of the first direction X is less than or equal to 2 mm, it is possible to reduce the space occupied by the portion of the diaphragm 130 extending beyond the second electrode piece 120, thereby helping to improve the energy density of the battery cell 10; therefore, when the width D3 of the portion of the diaphragm 130 extending beyond the second electrode piece 120 along the perpendicular direction of the first direction X is 0.1 mm-2 mm, which is possible to facilitate the mutual connection of the edge areas of the two layers of diaphragms 130 on both sides of the first electrode piece 110 or the second electrode piece 120, thereby reducing the possibility of short circuit between the first electrode piece 110 and the second electrode piece 120, thereby helping to improve the energy density of the battery cell 10.

[0158] In some embodiments, 0.2 mm ≤ D3 ≤ 1 mm. For example, D3 can be 0.2 mm, 0.5 mm, or 1 mm. This can not only facilitate the connection of the edge regions of the two layers of separator 130 on either side of the first electrode 110 or the second electrode 120, thereby reducing the possibility of short circuit between the first electrode 110 and the second electrode 120, but also help further improve the energy density of the battery cell 10.

[0159] 12 and 13 , FIG12 is a schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application, and FIG13 is a partially enlarged schematic diagram of a cross-sectional structure of a partial structure of the battery cell in FIG12 along EE.

[0160] In some embodiments of the present application, along the first direction X, the first empty foil areas 112 of the plurality of first pole pieces 110 are gathered toward the middle and connected.

[0161] In the present application, gathering the empty foil areas refers to pressing the empty foil areas together along the first direction X until they are in contact.

[0162] By allowing the first hollow foil areas 112 of the multiple first electrode sheets 110 to converge toward the center and connect along the first direction X, the connection method of the multiple first hollow foil areas 112 can be simplified and easy to operate, and the multiple first hollow foil areas 112 can be easily led out of the battery cell 10 for connection to external devices. In addition, because some first hollow foil areas 112 need to be bent and extended to a certain length before they can be connected to adjacent first hollow foil areas 112, by allowing the first hollow foil areas 112 of the multiple first electrode sheets 110 to converge toward the center, the size of the first hollow foil areas 112 in their extension direction (i.e., the direction perpendicular to the bent edge of the first hollow foil areas 112) can be reduced, thereby reducing the space occupied by the first hollow foil areas 112, which is beneficial for improving the energy density of the battery cell 10.

[0163] In some embodiments, along the first direction X, the second empty foil areas 122 of the plurality of second pole pieces 120 are gathered toward the middle and connected.

[0164] By making the second empty foil areas 122 of the multiple second pole pieces 120 converge and connect toward the middle along the first direction X, the connection method of the multiple second empty foil areas 122 can be simpler and easier to operate, and it is convenient for the multiple second empty foil areas 122 to be led out of the battery cell 10 to be connected to an external device. In addition, the size of the second empty foil area 122 in its extension direction (i.e., the vertical direction of the bent edge of the second empty foil area 122) can be made smaller, so that the space occupied by the second empty foil area 122 is smaller, which is beneficial to improving the energy density of the battery cell 10.

[0165] In some embodiments, the collapsed height of the plurality of first empty foil regions 112 is D4, and the thickness of the electrode assembly 100 is D5, satisfying 0.3≤D4 / D5≤0.7. For example, D4 / D5 can be 0.3, 0.5, or 0.7.

[0166] By ensuring that 0.3≤D4 / D5≤0.7, multiple first empty foil areas 112 can be easily folded and connected, so that the size of the first empty foil areas 112 in the extension direction can be set smaller, thereby reducing the space occupied by the first empty foil areas 112, which is beneficial to improving the energy density of the battery cell 10.

[0167] In some embodiments of the present application, the plurality of first hollow foil regions 112 include two outermost hollow foil regions 112a, wherein the angle between the bent edges of the outer hollow foil regions 112a and the length direction of the first electrode sheet is α1, satisfying 0<α1≤90°. The angle between the bent edges of the outer hollow foil regions 112a and the width direction of the first electrode sheet is α2, satisfying 0<α2≤90°.

[0168] By making the angle between the bending edge of the outer hollow foil area 112a and the length direction of the first electrode piece α1, satisfying 0<α1≤90°; the angle between the bending edge of the outer hollow foil area 112a and the width direction of the first electrode piece α2, satisfying 0<α2≤90°, the bending edge of the outer hollow foil area 112a can be inclined relative to the length direction and the width direction of the first electrode piece, thereby making the bending edge longer and the first hollow foil area 112 having higher impact resistance.

[0169] In some embodiments, the plurality of second hollow foil regions 122 include two outermost second outer hollow foil regions 122a. The angle between the bent edge of the second outer hollow foil region 122a and the length direction Y of the second electrode sheet is α3, satisfying 0<α3≤90°. The angle between the bent edge of the second outer hollow foil region 122a and the width direction Z of the second electrode sheet is α4, satisfying 0<α4≤90°. The bent edge of the second outer hollow foil region 122a can be tilted relative to the length direction Y and the width direction Z of the second electrode sheet, thereby making the bent edge longer and the second hollow foil region 122 having higher impact resistance.

[0170] In some embodiments, the battery cell 10 further includes a first adapter 114 and a second adapter 124, wherein one end of the first adapter 114 is connected to the first empty foil area 112, and the other end extends out of the outer shell 200; one end of the second adapter 124 is connected to the second empty foil area 122, and the other end extends out of the outer shell 200, for realizing the connection between the electrode assembly 100 and an external device.

[0171] Table 1 Energy density improvement rate, drop pass rate, and long cycle pass rate tests of battery cells See Table 1, in which D1 is the distance between one end of the second electrode 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the shell 200 along the length direction Y of the second electrode; S1 is the projected area of ​​the first empty foil area 112 along the first direction X; S2 is the area of ​​the first notch 111. In some embodiments, the test method for the energy density of the battery cell 10 is: (1) The battery cell is placed in an environment of 25±2°C. (2) The battery cell is charged to the charging cut-off voltage of the battery (such as 4.45V) at a constant current of 0.2C, and the battery cell is charged to 0.025C at a constant voltage. (3) The battery cell is discharged to the discharge cut-off voltage of the battery (such as 3.0V) at a constant current of 0.2C, and the discharge capacity of the battery cell is extracted. (4) Repeat the above steps 3 times, and take the average discharge capacity as the actual discharge capacity. (5) The energy density ED of the battery cell = actual discharge capacity × discharge platform / (battery cell volume). In this application, the battery energy density improvement rate is calculated based on Comparative Example 2. In Comparative Example 2, the electrode of the battery cell is not provided with a notch, and the first empty foil area and the second empty foil area of ​​the battery cell are provided at one end of the battery cell along its length direction. In Comparative Example 2, D1 is approximately 1.58 mm. Comparative Examples 1 and 3 are similar to the structure of the battery cell in the present application. In some embodiments, the drop test method includes: (1) fully charging the battery cell sample at 23±2°C, measuring and recording the open circuit voltage and battery impedance of the battery cell sample; (2) freely dropping the battery cell sample from a height of 1.5m (measured from the lowest point of the battery cell sample to the falling surface) onto concrete, and performing 5 rounds of drop tests, with the order of one round of drop being: front-back-bottom-top-left-right-upper left corner-upper right corner-lower left corner-lower right corner. (3) counting and observing the appearance of the battery cell, and the criteria for passing the drop test are: the battery cell sample does not explode, smoke, catch fire, or leak liquid within 1 hour after being dropped; the open circuit voltage of the battery cell 24 hours after the drop must not be lower than 90% of the initial value before the drop. In some embodiments, the test method for the long cycle 1000CLS pass rate includes: (1) fully charging the battery sample at 23±2°C and then discharging it, which is counted as one cycle; (2) after the battery sample is charged and discharged for 1000 cycles, the appearance of the battery sample is counted and observed, and the judgment criteria for the long cycle 1000CLS pass are: the battery cell energy decay does not exceed 20%, and the battery cell expansion does not exceed 8%. According to Table 1, the following conclusions can be drawn: (1) Referring to Comparative Examples 1-3 and Examples 1-5, when D1 is less than 0.1mm, although the energy density of the battery cell is high, the long cycle 1000CLS pass rate of the battery cell is low, which affects the service life of the battery cell; when D1 is greater than 1.5mm, the energy density of the battery cell is low; and when D1 is 0.1mm-1.5mm, the energy density of the battery cell is high, and the drop pass rate of the battery cell is high, and the possibility of damage when subjected to external force or dropped is low, the long cycle 1000CLS pass rate of the battery cell is high, and the service life of the battery cell is longer.(2) Referring to Examples 1-5, as D1 decreases, the energy density of the cell increases; the smaller D1 is, the higher the drop pass rate of the cell is, but the longer cycle 1000CLS pass rate is, the lower it is. (3) Referring to Examples 3, 6-12, S1 is less than 5mm. 2 When the battery is larger than 70mm, the energy density of the battery is higher, but the drop pass rate of the battery is lower, and the battery is more likely to be damaged when subjected to external force or dropped; S1 is greater than 70mm 2 When the energy density of the battery cell is low, the energy density of the battery cell is low; while S1 is 5mm 2 -70mm 2 When S1 is less than 5mm, the energy density of the battery cell is higher, and the drop pass rate of the battery cell is higher. The possibility of damage when subjected to external force or dropped is lower. The long cycle 1000CLS pass rate of the battery cell is higher, and the service life of the battery cell is longer. (4) See Examples 3, 7-11. As S1 decreases, the energy density of the battery cell becomes higher and higher. When S1 is smaller, it may affect the drop pass rate of the battery cell. (5) See Examples 3, 13-19. S2 is less than 5mm. 2 When the battery is larger than 70mm, the energy density of the battery is higher, but the drop pass rate of the battery is lower, and the battery is more likely to be damaged when it is subjected to external force or dropped; S2 is greater than 70mm 2 When the energy density of the battery cell is low, the energy density of the battery cell is low; while S2 is 5mm 2 -70mm 2 When S2 is low, the energy density of the battery cell is high, and the drop pass rate of the battery cell is high. The possibility of damage when subjected to external force or dropped is low. The long cycle 1000CLS pass rate of the battery cell is high, and the service life of the battery cell is longer. (6) Referring to Examples 3, 14-18, as S2 decreases, the energy density of the battery cell becomes higher and higher; when S2 is small, it may affect the drop pass rate of the battery cell. The embodiment of the present application provides an electrical device, and the electrical device includes the battery cell 10 provided in any of the above embodiments, and the battery cell 10 is used to provide electrical energy. The electrical device can be any of the aforementioned devices or systems using the battery cell 10. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0172] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: shell; an electrode assembly housed in the housing, the electrode assembly being a laminated structure, comprising a plurality of first electrode sheets and a plurality of second electrode sheets stacked along a first direction, the first electrode sheets and the second electrode sheets having opposite polarities, each of the first electrode sheets having a first notch, each of the second electrode sheets having a second notch, and the first notches and the second notches not overlapping when viewed along the first direction; Each of the first pole pieces has a first empty foil area that at least partially overlaps with the second notch, and the first empty foil areas of the plurality of first pole pieces are stacked along the first direction; Each of the second pole pieces has a second empty foil area that at least partially overlaps with the first notch, and the second empty foil areas of the plurality of second pole pieces are stacked along the first direction; The second notch and the second empty foil area are located at one end of the second electrode piece in the length direction, and the second notch and the second empty foil area are spaced apart along the width direction of the second electrode piece; Along the length direction of the second pole piece, a distance D1 is between one end of the second pole piece where the second hollow foil area and the second notch are provided and the inner wall of the housing, satisfying 0.1 mm ≤ D1 ≤ 1.5 mm.

2. The battery cell according to claim 1, characterized in that 0.3mm≤D1≤1mm.

3. The battery cell according to claim 1, characterized in that The first pole piece has a first angular position and a second angular position, the second pole piece has a third angular position and a fourth angular position, the first notch is located at the first angular position of the first pole piece, and the first empty foil area is located at the second angular position of the first pole piece; The second notch is located at the third corner of the second pole piece, and the second empty foil area is located at the fourth corner of the second pole piece.

4. The battery cell according to claim 3, characterized in that The first angular position and the second angular position are two adjacent angular positions of the first pole piece; The third angular position and the fourth angular position are two adjacent angular positions of the second pole piece.

5. The battery cell according to claim 1, characterized in that The first pole piece has a first coating area. Along the length direction of the first pole piece, the first empty foil area does not exceed the first coating area; along the width direction of the first pole piece, the first empty foil area does not exceed the first coating area.

6. The battery cell according to claim 5, characterized in that The first coating area has a first edge in the length direction of the first pole piece and a second edge in the width direction of the first pole piece; The first empty foil area has a third edge in the length direction of the first pole piece and a fourth edge in the width direction of the first pole piece; The third edge is flush with the first edge, and the fourth edge is flush with the second edge.

7. The battery cell according to claim 1, characterized in that The projection area of ​​the first empty foil area along the first direction is S1, which satisfies 5mm 2 ≤S1≤70mm 2 .

8. The battery cell according to claim 7, characterized in that: 10mm 2 ≤S1≤60mm 2 。 9. The battery cell according to claim 1, characterized in that: The maximum dimension of the first empty foil area in the length direction of the first electrode piece is L1, which satisfies 1mm≤L1≤15mm; The maximum size of the first empty foil area in the width direction of the first electrode piece is W1, which satisfies 1mm≤W1≤15mm.

10. The battery cell according to claim 9, characterized in that: 3mm≤L1≤10mm, 3mm≤W1≤10mm.

11. The battery cell according to claim 1, characterized in that The area of ​​the first gap is S2, which satisfies 5mm 2 ≤S2≤70mm 2 .

12. The battery cell according to claim 11, characterized in that 10mm 2 ≤S2≤60mm 2 。 13. The battery cell according to claim 1, characterized in that The maximum dimension of the first notch in the length direction of the first pole piece is L2, which satisfies 1mm≤L2≤15mm; The maximum dimension of the first notch in the width direction of the first pole piece is W2, which satisfies 1mm≤W2≤15mm.

14. The battery cell according to claim 13, characterized in that: 3mm≤L2≤10mm, 3mm≤W2≤10mm.

15. The battery cell according to claim 1, characterized in that The electrode assembly also includes a diaphragm, which is arranged between the first electrode plate and the second electrode plate. The diaphragm has a third notch and a fourth notch. Along the first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch.

16. The battery cell according to claim 1, characterized in that The electrode assembly further includes a separator, the first electrode piece is a positive electrode piece, and the second electrode piece is a negative electrode piece; The battery cell is a soft-pack battery cell, and along the first direction, edge regions of the two layers of the diaphragm located on both sides of the second pole piece are connected to each other.

17. The battery cell according to claim 1, characterized in that The electrode assembly further includes a separator, the first electrode piece is a positive electrode piece, and the second electrode piece is a negative electrode piece; The battery cell is a hard shell battery cell, and along the first direction, edge regions of the two layers of the diaphragms located on both sides of the first pole piece are connected to each other.

18. The battery cell according to claim 1, characterized in that Along the first direction, the first empty foil areas of the plurality of first pole pieces are gathered toward the middle and connected; and / or, along the first direction, the second empty foil areas of the plurality of second pole pieces are gathered toward the middle and connected.

19. The battery cell according to claim 1, characterized in that: The multiple first empty foil areas include two outer empty foil areas located on the outermost sides, and the angle between the bent edges of the outer empty foil areas and the length direction of the first pole piece is α1, satisfying 0<α1≤90°; the angle between the bent edges of the outer empty foil areas and the width direction of the first pole piece is α2, satisfying 0<α2≤90°.

20. An electrical device, characterized in that: The electrical device comprises the battery cell according to any one of claims 1 to 19, and the battery cell is used to provide electrical energy.

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